A wide variety of medical treatments utilize the delivery and introduction of therapeutic compositions to a treatment location in a patient. In home or outpatient settings, the delivery methods used can include procedures such as oral delivery or inhalants, while in clinical or hospital types of settings, a therapeutic fluid is often injected using a needle-based system. In more complicated methods, a fluid can be delivered surgically through a tubular device, such as a catheter or endoscope, and in some cases, the surgical method can involve minimally invasive procedures.
When liquid medications are administered using methods such as oral medication administration (i.e., swallowing the medication) or receiving the medication via a needle-based injection or a drip line, the amount of medication being dispensed is typically easily controllable and verifiable using simple measuring and/or viewing techniques. However, when the fluid is delivered to the patient internally through a tubular device, the ability to observe and adjust the medication administration can be more difficult. Thus, a number of systems have been developed for delivering therapeutic fluids to treatment sites within a patient that include minimally invasive, tubular delivery lumens (e.g., catheters or endoscopes) and fluid sources that are actuated by a plunger. This plunger can help the user to control the amount of fluid that is delivered to and/or expelled from the system. In some cases, the minimally invasive fluid delivery systems are not reusable, as the cost to sterilize the components can be prohibitive. These systems can include needleless fluid injection systems, for example. Needleless devices and methods for treating tissue of the urinary tract are discussed in Applicants' copending application U.S. Patent Application Publication No. 2006/0129125 and U.S. Ser. No. 12/087,231, filed Jun. 27, 2008 (Copa et al.), titled “Devices, Systems, and Related Methods for Delivery of Fluid to Tissue”, the entire disclosures of which are incorporated herein by reference.
Another issue that can be encountered with these fluid delivery systems is that a specific configuration of a system may not be adaptable or adjustable for use with multiple fluids having differing material properties, such as viscosity. In particular, these existing systems can often include long tubular components through which fluid needs to travel, such as one or more elongated lumens or catheters, and fluids with different viscosities can react differently to the resistance and friction encountered when moving through fluid tubular components. Due to this resistance, a fluid with a particular viscosity may exit the distal delivery end of an injection orifice with a significantly different amount of pressure or force than a fluid having a different viscosity when using the same injection pressure. If the exit force of the fluid is too high or low, the fluid administration at the treatment site may be ineffective. In addition, differences in the mechanical features of the system may contribute to or cause reduced or enhanced delivery pressure and/or fluid delivery velocity.
Due to the widely varied system and fluid requirements associated with the delivery of therapeutic compositions to treatment locations in a patient, there is a need to provide improved procedures, systems, and components for fluid delivery. Such procedures, systems, and components would provide for accurate and controlled dispensing of therapeutic compositions to specific treatment locations within a patient, and further would compensate for different fluid properties, such as viscosity.